A Content Decryption Module (CDM) is a component of digital rights management (DRM) systems that provides decryption services for protected content. The CDM is responsible for securely decrypting encrypted digital content, such as video or audio streams, and making the decrypted content available to the player for playback. The CDM is typically implemented as a closed-source component and is tightly integrated with the DRM system, to ensure that the content remains protected even when it is being played.
Here are a few useful links that provide information about the Content Decryption Module (CDM):
W3C specification for Encrypted Media Extensions (EME): https://www.w3.org/TR/encrypted-media/
Overview of DRM and CDM technology: https://en.wikipedia.org/wiki/Digital_rights_management
Information on the use of CDMs in web browsers: https://developer.mozilla.org/en-US/docs/Web/DRM
CDM security and privacy considerations: https://www.eff.org/issues/drm-and-privacy
These resources should help you gain a deeper understanding of CDMs and their role in digital rights management.